Research On Engine Control Based On CAN In Automated Mechanical Transmission

The technology of automatic transmission has become an important field in improving vehicle and consummating driving train. Since the hydraulic torque converter was invented in 1939, automatic transmission technology has gotten a long development. Especially the use of modern microelectronic technique on vehicle makes the application of automatic transmission more and more extensive.The Automatic Mechanical Transmission (AMT) bases on the traditional fixed shaft-type Mechanical Transmission (MT) and is installed Auto Shift Control System (ASCS).The Transmission Control Unit (TCU) controls the actuator and sends out the require for shifting according to the driver,substituting the manual movements to complete shifting. This kind of design can effectively reduce the differences and the fatigue strength between different drivers,enhance the driving security and advance the power and the economy of the automobile.Among some traditional automated transmissions(AT,CVT,AMT),AMT has the highest ratio of quality to price. It not only possesses the advantage of the hydraulic automated transmission, but also reserves the superiority of high efficiency, low cost, simple structure and easy manufacture in manual transmission. It has potentially amplitude applications in cars,city buses,military vehicles and carry cargo cars. So, compared with the other automated transmissions , like AT and CVT,AMT is more fit for the situation of Chinese market and it has more market and long potentials. It deserves being widely developed.With the progressive development of technology of engine control and the automated transmission, the enhance of control function of ECU and development of related control theory, a kind of dwhich connects engine control and transmission control has become a trend. Depending on the rapid development of microelectronic technique, it has become a trend to realize the optimum matching between engine and transmission. By accurate control of engine and transmission, the transmission without clutch operating will necessary become a trend of AMT in the future.The main designing idea of no-separated-clutch AMT bases on the electric control engine and use electric actuator to shift. While the vehicle is driving, in order to make the active and passive gear of transmission synchronous, AMT system can combine the retarder control to rapidly adjust speed or torque of engine by communicating with both CAN line and the ECU of engine. Meanwhile, by accurately controlling the speed, torque and position of shifting electromotor, AMT control system can realize shifting without clutch being separated.In the late of 2006, Shanxi Fast Gear Ltd., cooperating with Shanxi heavy vehicle Ltd., Jilin university and Chongqing university, carried on the national"eleventh five"863 project which is"the development in heavy commercial vehicle(2000N.M)". This project has been brought into the significant project of the modern transportation area. This thesis basing on the previously research aims at the engine control of AMT in heavy vehicle and carries on the related bench test and research. The main researching content includes the following aspects:1)By reading the related professional documents and studying the domestic and foreign materials, this paper summarizes the history and direction of automated mechanical transmission;It also introduces the structure and principle of operation, analyses the advantages brought by no-separated clutch and one technology difficulty which is the united control of both engine and the AMT.2) research on engine controlThis paper analyzes the no-load characteristic and proposes the main idea about engine control:according to the characteristic of throttle-velocity in no-load engine condition, combine throttle and velocity in the shifting process, and assign out the aimed throttle position according to the aimed speed. It also analyzes the operating characteristic of engine and transmission during the control in picking off , in neutral and the restoration control of throttle and basing on this proposes the detailed control strategy about engine control:the control in Picking off,requests to unload the engine,in the rotational speed invariable situation,the engine output torque should be turned to be zero; the control in neutral,requests the engine speed to finely adjust,makes the deviation between the rotational speed and the goal rotational speed enter the permission range of shifting; The restoration control of throttle,to restore power of the vehicles as soon as possible in the driving comfort scope.3) research on CAN line protocolThe paper introduces the history of CAN line protocol, analyses the similarities and differences between the edition 2.0A and 2.0B, deeply comprehends the detailed content of CAN1939 protocol; It also sums up the network model and topology structure of CAN protocol, making the request for each model clear; According to the structure of all kinds of frames, analyses the function desire of PDU and PGN, proposes the detailed CAN code protocol content of engine speed and torque.4) research on CAN line used in engineThe thesis designs the AMT hardware structure of TMS,TCS and analyses all the function system of SAKXC164CS singlechip. Basing on the request of data collection, makes the data collection card to collect the trial data; design the united structure of AMT software, according to the basic parallel circuit principle , makes use of Visual Basic software to develop data collecting programs, at the same time ,collecting eight ports data including percent torque,speed,pedal position e.g. According to the request of CAN line application, develop programs to realize the communication between AMT system and ECU system. Separately analyze the practical application method in the course of picking off , neutral and the restoration control of throttle. Analyze the control instruction in the three processes, write out the PDU structure and complete the enter of control data.5) research on engine control in no-load situationAnalyze the basic function of AMT synthesized bench test, set up the bench test and get the trial parameters including engine, transmission, operating motor and sensors. Make use of CAN line function, separately do experiments about the engine speed up and down in the no-load condition and then increase the PID control method on the experiment to optimize the results. By the way of matlab software, draw the trial data out and analyze the result, mainly achieve the aims of making use of CAN line to control engine.